The STIS Close-Out Plan:
Closeout Activities after the STIS failure of August 4, 2004
Paul Goudfrooij and the STIS Team (see acknowledgments)
STIS Team Charter
The STIS Team (part of the Spectroscopy Branch of the Instruments Division) is charged with maximizing the
scientific return of data from the Space Telescope Imaging Spectrograph, providing continued archival support for
STIS and the older heritage HST spectrographs, and interfacing with other activities at STScI directed at the scientific
productivity of HST and the STScI’s future as defined in the STScI Long Range Plan.
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Overview
This STIS Close-Out Plan describes the plan goals, its organization, the general nature of the close-out activities,
and details on each major activity. As of November 1, 2004, the Team consists of 5 instrument scientists and
4 data analysts (DAs). Programming support is provided by members of the Science Software Branch (SSB) in
the Engineering and Software Services (ESS) division. Taking the functional time that has been matrixed into the
group for each of the individuals and allowing for an appropriate amount of personal leave, detailed tasks have been
established as a function of time which are itemized on Excel spreadsheets.
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Close-Out Plan Goal
The huge archive of STIS observations constitutes a unique —and arguably the most comprehensive— source of
spectroscopy in the UV and spatially-resolved spectroscopy in the UV and optical regions available to the entire
astronomy community. The main goal of the STIS close-out plan is therefore to render the full archive of STIS data
in a calibration status suitable for performing high-level and high-accuracy science before STIS support at STScI is
phased out. The goal for the final overall level of calibration accuracy to be reached for all (previously) supported
STIS observing modes is advertised in Chapter 16 of the STIS Instrument Handbook:
http://www.stsci.edu/hst/stis/documents/handbooks/currentIHB/stis ihbTOC.html.
In addition, we intend to implement software improvements as well as enhancements related to the retrieval of STIS
data from the HST archive. Detailed information on the various close-out activities is presented in Section 5 below.
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STIS Team Organization
The organization of the Team will remain relatively unchanged from previous plans. Team efforts are divided
managerially and conceptually into “Blocks”. Most Blocks are led by a “Block Head” and a lead DA who are
responsible for planning the work within the Block and reporting on its progress. We also assign a main Backup
scientist for each block (if appropriate), to act as Block Head if the main Head is on leave. The scientists and DAs
within the Team typically work in multiple blocks, in a matrixed fashion. The Blocks and Block Heads for FY05 are
mentioned in Table 1 below. Details on the formal responsibilities of each Block are listed in the Appendix.
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Nature of Closeout Activities
The closeout activities described below belong to one of the following three main classes:
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Table 1: STIS Team Blocks, Block Heads, their Backups, and Lead DAs
Block
Block Head
Backup
Lead DA
Calibration
Pipeline
User Support
Information
Hardware/Software
Management
Dressel
Proffitt
Maı́z
Aloisi
Kim
Goudfrooij
Goudfrooij
Aloisi
Davies
Diaz-Miller
Kim
Kim
Kim
Dressel
Proffitt
1. Already planned tasks of moderate-to-high priority which did not come to completion by the end of FY04.
These tasks are related to STIS calibration of regularly used observing modes and the subsequent implementation into software (within the pipeline or as off-line IRAF tools);
2. New tasks related to, e.g., the enhancement of archive capabilities regarding STIS data, or to a proper documentation of all activities regarding the use of STIS data and of the monitoring activities used by the STIS
branch over the years;
3. Tasks related to the implementation by STScI of the software and other deliverables created by the Space
Telescope-European Coordinating Facility (ST-ECF) in Germany as part of its STIS-CE (Calibration Enhancement) project.
We note that activities related to the possible servicing of STIS during a robotic Servicing Mission #4 (SM4) have
not yet been considered at this time. (If a decision is made along the way to service STIS during SM4, then numerous
extra activities will need to be added to the STIS Team plan in FY07.)
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Details on the closeout activities
The proposed closeout activities are listed on Excel spreadsheets, along with an estimated percentage of STIS users
aided by that activity and an assigned overall priority for each activity. In this section, we describe in some detail
those activities that will incur some significant effort by the STIS Team. Usage statistics and priority assignments
are indicated for each activity in blue and red, respectively. The activities are divided up in catagories, largely by
Block as listed in Table 1 above. STScI terms and acronyms used in this section are explained below.
CALSTIS
ESS
GO
IHB
ISR
OTFR
Reference File
TIR
SSB
The STIS Calibration Pipeline software suite.
Engineering and Software Services, a Division within STScI.
General Observer
Instrument Handbook
Instrument Science Report (STIS ones available through www.stsci.edu/hst/stis/documents/isrs)
On-The-Fly Reprocessing (this occurs when requesting “calibrated” data from the HST Archive,
running the raw data through the HST pipeline with the most up-to-date calibration files)
These are used to calibrate STIS data in the HST Pipeline. They are generated from calibrations of
the instrument, and stored in the on-line database for use in OPUS and STSDAS data processing.
In order to ensure the most stable pipeline processing environment, any changes in instrument calibration parameters are most oftenly incorporated in the pipeline by delivering updated Reference
Files rather than making software changes.
Technical Instrument Report (these are of a technical nature, meant for STScI-internal users; STIS
ones are available from the STScI domain through www.stsci.edu/hst/stis/documents/tirs)
Science Software Branch (Part of the Engineering and Software Services Division within STScI).
This Branch is expected to be involved with a number of projects listed below, indicated as such.
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5.1
Calibration Block Activities
NUV-MAMA Prism Calibration (Usage: 5%)
(PRIORITY: Med/High)
The purpose of this activity is to finish the implementation of a new software package to enable wavelength calibration and time-dependent sensitivity calibration as well as geometric distortion correction of spectra taken in
the slitless Objective Prism mode of STIS, a mode which became increasingly popular during the last three HST
cycles (e.g., it was used by a prominent Treasury program in Cycle 12). This package enables the extraction of fluxcalibrated spectra for targets anywhere in the field of view of the detector, using two STIS images as input: a direct
image taken in a NUV-MAMA imaging mode and a PRISM image. The calibrations needed for this task to succeed
have been bootstrapped from analysis of a suitable set of calibration data. This activity involves the conversion of
a software script (currently available as IDL routine) into a STSDAS task by the Science Software Branch. An ISR
will also be issued.
L– and M-mode Sensitivities (Usage: 45%)
(PRIORITY: High)
These activities will deliver the final sensitivity calibrations for the first-order spectroscopic modes of STIS, using
both primary and secondary (from the sensitivity monitoring data) spectrophotometric standard stars. This includes
final reference file updates for wavelength-dependent aperture corrections, wavelength-dependent extraction size
corrections, and wavelength-dependent time dependences, using all calibration data collected through the summer
of 2004.
Program Numbers: 10030, 10033, 10039
E-Mode Sensitivities (Usage: 30%)
(PRIORITY: Crucial)
This activity will deliver the final sensitivity calibrations for the echelle modes of STIS. This includes final reference
file updates for wavelength-dependent aperture corrections, wavelength-dependent extraction size corrections, and
wavelength-dependent time dependences, using all calibration data collected through the summer of 2004. The
SYNPHOT component files for the echelle modes also need to be updated (the current versions are not consistent
with the photometric sensitivity reference files in the pipeline; e.g., the former do not include the echelle blaze
functions, only the ‘envelope’ of the sensitivity curves). This is a high-priority item (and has been for two years, but
staff reassignments have delayed progress); current E-mode sensitivity reference files stem from 1997. This activity
will also involve writing an ISR.
Program Numbers: 8915, 8919, 9628, 10033
E-Mode Sensitivity Uncertainty due to Monthly Offsets (Usage: 30%)
(PRIORITY: High)
This activity is related to the previous one but is listed separately because it includes the complicated effort to derive
a correction for the so-called Monthly Offsets and their associated blaze shifts, which do not repeat well for a given
month of the year (i.e., the time dependence of the amplitude of the blaze shifts is currently not adequately corrected
for). This effort shall be performed for both primary and secondary central wavelength settings, as they have had
similar usage by GOs. This activity will involve writing at least one ISR, and may involve the need for code changes
within CALSTIS.
Program Numbers: 8915, 8919, 9619, 9628, 10033
This item may well require SSB resources
CCD and MAMA Full-Field Sensitivity Monitors (Usage: 20%)
(PRIORITY: Medium)
These activities comprise flux measurements of various isolated stars covering the field of view of the three STIS
detectors, from images that are taken at regular time intervals so that the same star is imaged on different parts of the
detector. These data are used to monitor the full-field sensitivity of the detectors as well as the astrometric and PSF
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stabilities. The data from Cycles 11 and 12 will have to be analyzed. The results will be compared to the previously
determined time dependence of the sensitivity for the different imaging modes, and to evaluate the need for updates
to the low spatial frequency flat fields for imaging modes. This activity will involve writing two ISRs (one for the
CCD and one for the two MAMA detectors).
Program Numbers: 9622, 10028, 9623, 10032
MAMA Dark Monitor (Usage: 65%)
(PRIORITY: High)
This activity involves the measurement of the dark current levels of the two MAMA detectors, which have been
taken twice a week for each detector. The NUV-MAMA dark data taken over the years will be assembled together to
determine final functional forms of the global dark current levels as a function of time, tube temperature, and charge
amplifier temperature. These scaling functions will be implemented into the STIS calibration pipeline (CALSTIS),
involving new reference files as well as a code change. In the case of the FUV-MAMA detector, additional work is
needed to determine a better parametrization of the dark level in the “glow” region of the detector. We already have
a good idea on this from earlier preparation work, namely to parametrize the FUV-MAMA dark level as a function
of the time elapsed since the high-voltage was turned on. For a “heritage” instrument, this can be implemented by
delivering a reference table containing the turn-on times, or as a post-observation tool using another proxy that is
dependent on the time elapsed since the high-voltage was turned on, e.g., the intensity level of hot pixels. These
findings will be written up as two ISRs.
Program Numbers: 9615, 10034
This item will require SSB resources
CCD Dark Monitor (Usage: 35%)
(PRIORITY: High)
This activity involves a thorough investigation of the evolution of the CCD darks as a function of time, including the
number of hot pixels at different intensity levels and as a function of row number (indicating the evolution of CTE
loss). The main purposes of this activity are to provide useful information on the behavior of the performance of
CCDs (of different architecture) in orbit, and to compare the results with the performance of other CCDs on HST.
This activity will involve writing one ISR.
Program Numbers: Many (two per cycle)
CCD Anneal (Usage: 35%)
(PRIORITY: High)
This activity involves a re-evaluation of the monthly growth in the hot pixel rate (at different intensity levels) and
the effectiveness of the anneal over time. Essentially an update of the early ISR written in 1998, now with all
annealing data accumulated to summer 2004. The main purposes of this activity are to provide useful information
on the behavior of the performance of CCDs (of different architecture) in orbit, and to compare the results with the
performance of other CCDs on HST.
Program Numbers: Many (one per cycle)
CCD Spectroscopic Flats (Usage: 25%)
(PRIORITY: Med/High)
This activity involves a re-evaluation of the time and wavelength dependences of the CCD spectroscopic flat field
(on both low and high spatial frequencies), and to recreate flats for each mode with higher-S/N than those currently
available. This activity will involve writing one ISR.
Program Numbers: Many (one per cycle)
CCD Imaging Flats (Usage: 10%)
(PRIORITY: Medium)
This activity involves a re-evaluation of the time dependence of the CCD imaging flat field (on both low and high
spatial frequencies), and to recreate flats for each of the four CCD imaging modes with higher-S/N than those
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currently available. This activity will involve finishing the automatic reference file creation software for this mode,
and writing one ISR.
Program Numbers: Many (one per cycle)
CCD Internal Sparse-Field CTE monitor (Usage: 35%)
(PRIORITY: High)
This activity involves the analysis of the last two epochs of the Internal Sparse-Field CTE monitor calibration
program. This program is used to quantify two key aspects of CTE performance: The amount of charge lost outside
a spectral extraction aperture and the amount of centroid shift experienced by the charge remaining within that
aperture. This test is done for 5 different signal levels; since the test is extremely stable (using internal lamps) and it
has a pre-launch measurement available, it constitutes the best calibration data to derive the time dependence of the
CTE of the STIS CCD. The results will also be compared to those derived from the physical model of CTE loss of
the STIS CCD by P. Bristow of the ST-ECF (see below). This activity will involve writing one ISR.
Program Numbers: Many (one per cycle)
CCD External Sparse-Field CTE monitor (Usage: 35%)
(PRIORITY: High)
This activity involves the analysis of the last two epochs of the External Sparse-Field CTE monitor calibration
program. These data bear directly on the influence of CTE effects to the accuracy of point source photometry
and spectroscopy. The analysis has been described by Goudfrooij & Kimble in the Proceedings of the 2002 HST
Calibration Workshop. The results will also be compared to those derived from the physical model of CTE loss of
the STIS CCD by P. Bristow of the ST-ECF (see below). This activity will involve writing two ISRs, and it will also
be used in the final version of a manuscript on the CTE performance of the STIS CCD, to be submitted to PASP.
Program Numbers: Many (one per cycle)
CCD CTE effect on Extended Sources (Usage: 20%)
(PRIORITY: High)
This activity involves the analysis of data observed during three calibration programs to determine the effects of
CTE loss to surface photometry and spectroscopy of extended sources, as well as the time dependence of those
effects: (i) the effects of CTE loss to CCD imaging of galaxies (e.g., luminosity, ellipticity, and position angle
measurements at a given surface brightness), (ii) The effect of CTE loss to continuum fluxes and emission-line
intensities in spectroscopy mode; (iii) The effect of CTE loss to absorption-line intensities, profiles, and equivalent
widths in spectra. All results mentioned above will be compared to the correction applied by the physical model
of CTE loss of the STIS CCD by P. Bristow of the ST-ECF (see below). In addition, the results from (ii) and
(iii) above will also be compared to the CTE correction provided by the STIS pipeline (derived from point source
spectrophotometry). This activity will involve writing three ISRs.
Program Numbers: 8839, 8927, 10038
Imaging Zeropoints and Color Terms (Usage: 30%)
(PRIORITY: High)
This activity involves the analysis of imaging data of sources with known photometry and covering a wide range of
(known) SEDs (spectral energy distributions). The analysis will involve deriving the influence of the intrinsic colors
to the derived zeropoints (i.e., the so-called ‘color terms’ in the photometric calibration), and a comparison with
predictions using synthetic spectra (using SYNPHOT). This activity will involve writing a PASP paper.
Program Numbers: Various
CCD Side-2 Gain Ratio Test (Usage: 10%)
(PRIORITY: Med/High)
This activity involves the analysis of observations of a bright spectrophotometric standard star with a wide slit with
the 3 low-dispersion CCD gratings at gain 1 and gain 4, so that the ratio of gain 4 to gain 1 can be measured. (This
will be used to calibrate gain 4 relative to gain 1, which is already well measured.) The target is placed both at
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the center of the detector and at a row close to the read-out amplifier, and short exposures are also taken, so that
CTE effects can be measured and calibrated out. Additional exposures are taken using the non-default amplifier B,
which is used for some calibration programs, so that the gains relative to amp D can be measured. This program
will provide an independent measurement of the gain ratio which is better than the technique of noise-vs-intensity
for flatfields which has been used previously. This activity will involve writing one ISR.
Program Numbers: 9611
MAMA First-Order Dispersion Solutions (Usage: 25%)
(PRIORITY: High)
This activity involves the analysis of deep first-order MAMA wavecals taken in the context of a calibration proposal.
Internal wavecals have been obtained at all primary and secondary central wavelengths. Exposure times were chosen
to yield enough strong emission lines to constrain adequate wavelength solutions. Data were taken at the zero
MSM offset position which is in the middle of the range covered by monthly offsets, and hence provides the best
average dispersion solution. Dispersion solutions will now be derived using the recently published Pt/Cr-Ne line
list (Sansonetti et al. 2004, ApJS, 153, 555). (Note that the current dispersion solutions were derived using a Pt-Ne
line list, even though the line lamps used on STIS were Pt-Cr-Ne hollow cathode lamps). A new dispersion ( dsp)
reference file will be created and delivered. An ISR describing dispersion changes as well as the accuracy of the
previously used dispersion solutions will be written and published.
Program Numbers: 9618
Sensitivities for the CCD E1 & E2 Apertures (Usage: 10%)
(PRIORITY: High)
This activity involves the analysis of sensitivity measurements of spectrophotometric standard stars taken at the E1
and E2 pseudo-aperture locations near CCD row number 900. By moving a spectrum closer to the readout, the
number of parallel charge transfers is reduced by about a factor of four, with a comparable reduction expected in the
losses due to charge transfer inefficiency during the readout. It remains to be checked, however, whether detector
sensitivity and focus near row 900 differ by a few percent from that near the middle of the detector. This would result
in errors in the extracted fluxes that might differ from aperture to aperture. This dataset also include observations
with a 5.5 pixel dither in the cross-dispersion direction both to provide sub-sampled PSFs and to check if small
variations in the target position have a significant effect on the measured count rates. This activity will involve
writing one ISR, and likely also an update of 1-2 reference files.
Program Numbers: 8916, 9616, 10039
Grating Scatter for the G230LB Grating (Usage: 5-10%)
(PRIORITY: Medium)
This activity involves the analysis of measurements of red targets taken with both the NUV-MAMA/G230L and
CCD/G230LB modes. The goal is to determine a correction for the influence of grating scatter (primarily from the
far wings of the LSF, similar to the effects seen before for the UV gratings used in the Faint Object Spectrograph) in
case of CCD/G230LB spectra of red targets.
Program Numbers: 7723
Spectroscopic PSF Across Slit (Usage: 10%)
(PRIORITY: High)
This calibration activity involves the characterization of the PSF across the slit for two commonly used long slits
(52x0.1 and 52x0.2). Multiple G750L spectra are taken of a K giant star, stepping the slit across the star between
exposures to sample the PSF along the dispersion direction. For chosen wavelength intervals, the relative fluxes in
each slit position and spectral row are compared to the values predicted using TinyTim models. It is important to
verify these models since they are used as input in the dynamical modelling of spectral images, e.g., in the dynamical
modelling of galactic nuclei. This activity will involve writing one ISR.
Program Numbers: 9610
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Faint Standards Extension (Usage: 10%)
(PRIORITY: High)
This activity involves analysis of CCD spectra of (faint) white dwarfs which were previously identified and verified
as bona fide spectrophotometric standard stars. The purpose of this analysis is to provide a thorough verification of
the previously established CTE corrections for CCD spectroscopy, namely by stepping the target along the slit (5
positions) with two (short) exposure times. This will verify the results using the two-amplifier readout method, and
provide high-S/N data at low intensity levels and low background level. This activity involves the writing of one ISR
and may also involve an update of the CTE parameters in the CCD Table Reference File, if necessary.
Program Numbers: 10037, 10039
Reference File Deliveries (Usage: 100%)
(PRIORITY: Crucial)
This activity involves the generation and delivery of calibration reference files to several databases used by the
pipeline and the HST archive, namely the Calibration Data Base System (CDBS), Data Archive Distribution System
(DADS) and OSS and PODPS Unified System (OPUS). (OSS is the Observation Support System, and PODPS is the
Post-Observation Data Processing System.) The quality assessment of reference files as well as the verification of
their use in the STIS pipeline is performed by the STIS Team member who performed the calibration activity leading
to the creation of the reference file, while the actual deliveries and additional database-related verifications are done
by people within the Team specifically trained and dedicated to perform these tasks.
Trace Stability for Often-Used Modes (Usage: 15%)
(PRIORITY: High)
Spectral “trace” reference files prescribe the projection of spectra onto the detector at a given position along the
spectrograph slit. They are used to produce rectified spectral images and extracted spectra. Accurate traces are
needed when individual rows in spectral images are to be analyzed – e.g., in kinematic studies of galaxies, designed
to measure the masses of supermassive black holes in galactic nuclei. Accurate traces are also needed for photometric
accuracy when small extraction boxes are required to separate nearby point sources or to better isolate a point source
from more extended emission. The spectral traces now in use were created from inflight data taken early in the
orbital lifetime of STIS, and they can be seen to be in error in rectified spectral images taken in the last few cycles.
This project will use calibration as well as GO data to derive spectral traces near the center of the detector (and, for
CCD observations, at the E1 aperture positions), for the most commonly used gratings and central wavelengths at
several epochs. We will examine changes in rotation and shape of the traces, and produce new reference files where
needed. The highest-priority gratings and central wavelengths, selected by total science observing time, are the L
gratings as well as G750M at central wavelengths 6581, 6768, and 8561. Apart from the creation of calibration
reference files where needed, this project will involve the writing of an ISR.
5.2
Pipeline Block Activities
CCD and MAMA Temperature-Dependent Sensitivity (Usage: 100%)
(PRIORITY: High)
Recent investigations of the multivariate dependence of the sensitivity have revealed a significant dependence of the
MAMA and CCD modes on detector temperature. (For the CCD, this is only relevant after the switch to side 2
in July 2001, when the active temperature control of the Thermo-Electric Cooler was lost.) This dependence has
recently been documented in STIS ISR 2004-04. This activity involves the incorporation of a correction of this effect
in the STIS pipeline by means of the addition of an algorithm in a CALSTIS routine as well as the delivery of two
reference files. The latter reference files will have to be of a new type, so that their delivery process will require
somewhat more resources than usual.
This item will require SSB resources
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Rectification of Non-Dithered Spectra of Spatially Resolved Targets (Usage: 15%) (PRIORITY: Med/High)
This activity is to improve the quality of 1 – 3 pixel high extractions of STIS spectra taken with gratings for which
the traces are tilted significantly with respect to the CCD pixel array (especially G430M and G750M). The current
pipeline extractions use bilinear interpolation which produces strong undulations in spectral extractions of 1 – 3
pixels high. This activity is expected to involve interactions with the Eta Car Treasury Program who have already
implemented an interpolation routine which seems to work much better in that respect than that in our STIS pipeline.
This activity will also involve writing an ISR.
This item will require SSB resources (to implement a new interpolation routine)
Optimal Extraction Module (Usage: 10%)
(PRIORITY: Low/Med)
This activity involves finishing the implementation of an “optimal extraction” routine as an option within a CALSTIS
module (the x1d task), which will produce higher-quality extracted 1-D spectra than the current default extraction
routine. The coding and testing of this routine has been finalized in the past for all spectroscopic L modes as well as
the MAMA M modes, but support for the CCD M modes still remain to be finalized. We anticipate that this activity
will involve writing an ISR and making code changes within CALSTIS.
This item will require SSB resources
Imaging MultiDrizzle Testing (Usage: 25%)
(PRIORITY: High)
This activity involves the testing of the implementation of the STIS-specific modules within the MultiDrizzle code.
It includes the establishment of a STIS imaging testing suite covering every relevant imaging mode with all three
detectors, the testing of CR-rejection parameters (to work only for CCD imaging, not MAMA imaging), support of
multi-imset FITS files (which only exist for STIS data, not for the other (current) HST instruments), and various
other MultiDrizzle parameters as well.
This item requires SSB resources (within the MultiDrizzle project)
Spectral Dithering within MultiDrizzle (Usage: 15%)
(PRIORITY: High)
This activity will allow the handling of spectroscopic STIS data within the MultiDrizzle tool. The intent is to allow
combination of sets of spectral images which involve inter-exposure offsets (dithers) in the dispersion direction
(across the slit), the spatial direction (along the slit), or both. The correction for dithers in the dispersion direction
will involve calibrations that are dependent on grating and aperture. We anticipate that this activity will involve a
significant amount of testing by STIS Team members. It will also involve writing an ISR and —likely— the need for
delivery of reference files that allow for a correction of the throughput loss associated with stepping a source across
the slit.
This item will require SSB resources (within the MultiDrizzle project)
SYNPHOT TDS implementation TIR (Usage: 100%)
(PRIORITY: High)
This activity involves writing a Technical Instrument Report on the process used to implement the correction for
Time-Dependent Sensitivity of the various STIS modes within the SYNPHOT package, which also allowed this correction to be applied within the STIS Exposure Time Calculators. This recently finalized implementation involved
activities that are not normally encountered in deliveries of SYNPHOT reference files, it is important to have a clear
record of the steps involved in this delivery. Newer and upcoming instruments, especially those involving ultraviolet
imaging and/or spectroscopy, will likely have to deal with similar implementations.
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SYNPHOT Delivery Procedures TIR (Usage: 100%)
(PRIORITY: High)
This activity involves writing a TIR on the delivery procedures of SYNPHOT component files, including descriptions
of the several types of component files and how they are implemented within the SYNPHOT package. Some of these
descriptions were missing from the original SYNPHOT documents and have caused confusion among instrument
groups, hence the need for this report.
STScI/ST-ECF Collaboration Items (Usage: 50%)
(PRIORITY: High)
This activity involves STIS Team work related to the implementation of deliverables of the STIS Calibration Enhancement (STIS-CE) project within the STScI environment, be it decision making and/or providing assistance
regarding software modules within the CALSTIS pipeline, the STIS archive, or STIS-specific software to be released as IRAF/STSDAS tasks. The two main remaining projects related to ST-ECF deliveries will constitute (1) the
testing and possible implementation of a new, physical model-based wavelength calibration module for the echelle
gratings, and (2) the testing, evaluation, and possible implementation of the physical model-based correction for
CTE loss of the STIS CCD by P. Bristow.
This item will require SSB resources
Final Calibration of STIS Data (Usage: 100%)
(PRIORITY: High)
This activity involves a comprehensive run of all archival STIS data through OTFR once all final calibrations,
pipeline coding, and reference files have been tested and delivered to the various databases. The final set of calibrated STIS data will then be stored in the HST archive, and OTFR can be switched off for STIS use which would
make more processing power available for OTFR requests of active HST instruments. It would also render calibrated
STIS data to be readily available for viewing and plotting, which is relevant in the Virtual Observatory era.
This item will require Archive Branch resources
5.3
Archive Enhancement Activities
Imaging PSF Library (Usage: 15%)
(PRIORITY: Medium)
This activity involves the work needed to allow the user to retrieve well-exposed imaging PSFs in a given observing
mode (detector / filter combination) and location on the detector. This consists mainly of the identification and
assembly of a data base of appropriate datasets, the creation and implementation of a Graphic User Interface (DUI)
that performs the archive retrieval of the datasets involved, and the writing of an ISR (which can in principle be
combined with the next activity). It can be foreseen that the GUI mentioned above would be developed for all HST
instruments simultaneously.
This item will likely require SSB or ESS resources
Spectroscopic PSF Library (Usage: 30%)
(PRIORITY: Medium)
This activity involves the work needed to allow the user to retrieve well-exposed spectroscopic PSFs in a given
observing mode (detector / grating / slit combination) and location on the detector. This consists mainly of the
identification and assembly of a data base of appropriate datasets, the creation and implementation of a Graphic
User Interface that performs the archive retrieval of the datasets involved, and the writing of an ISR (which can
in principle be combined with the previous activity). It can be foreseen that the GUI mentioned above would be
developed for all HST instruments simultaneously.
This item may require SSB or ESS resources
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GO Wavecal Assocation (Usage: 10%)
(PRIORITY: Medium)
This activity involves the development and implementation of a system within OPUS and the archive that automatically associates STIS GO wavecals (i.e., wavecals inserted by STIS GO’s in their Phase-II proposals, which typically
happens when they were allowed to forego the default automatic insertion of wavecals) with the appropriate science
spectra, so that retrieval of the latter data will automatically attach the GO wavecals to them. (Currently, only science
data are returned (no wavelength calibration is performed by the pipeline), and the GO will need to issue a second
archive query to find the GO wavecals based on the proposal/visit combination of the science data. Note also that
if a calibrated spectrum is made without a proper wavecal, then serious errors in the wavelength and flux scales can
result.) It can be foreseen that this activity would be performed in concert with association-related activities for other
HST instruments.
This item will require OPUS and Archive resources
Fringe Flat Association (Usage: 10%)
(PRIORITY: Medium)
This activity involves the development and implementation of a system within OPUS and the archive that automatically associates contemporaneous STIS CCD Fringe Flats (which have been inserted by STIS GO’s in their Phase-II
proposals when G750L or G750M spectra were taken) with the appropriate science spectra, so that retrieval of the
latter data will automatically attach the appropriate fringe flats to them. (Currently, only the science data are returned and the GO will need to issue a second archive query to find the contemporaneous fringe flats based on the
proposal/visit combination of the science data.) It can be foreseen that this activity would be performed in concert
with association-related activities for other HST instruments.
This item will require OPUS and Archive resources
Spectroscopic Preview Enhancement (Usage: 75%)
(PRIORITY: High)
This activity involves the review and improvement of the “preview” facility available within the HST archive pages
for STIS spectra (the “Plot marked spectra” button), whose main purpose is to simplify the preparation of archival
studies or proposals. While this facility certainly provides useful output already, there are several aspects that can be
improved significantly, e.g., in the areas of the sky subtraction method currently in use and the automatic assignment
of display parameters that are often imperfect. Moreover, the facility should also be able to present a 2-D image of
the spectral data, so users can see the spatial extent of the target.
This item will require Archive Branch resources
Imaging Preview Facility (Usage: 25%)
(PRIORITY: Medium)
This activity involves the review and improvement of the “preview” facility for STIS image-mode data, whose main
purpose is to simplify the preparation of archival studies or proposals. While this facility certainly provides useful
output already, there are several aspects that can be improved significantly, e.g., in the areas of the algorithm that
assigns display parameters. This currently often leaves room for improvement.
This item will require Archive Branch resources
5.4
Information Block Activities
Data Handbook Update (Usage: 100%)
(PRIORITY: Crucial)
This activity involves a final review and update of the STIS chapter of the HST Data Handbook. The last update was
made before a significant number of updates to the CALSTIS pipeline and stand-alone tasks in the STIS package
within IRAF/STSDAS were implemented. Hence it is important to create a final, all-encompassing version of the
Data Handbook for STIS. It should include a data analysis “cookbook” to guide users in the routine analysis of STIS
spectral data. (This activity was planned already for the FY05 timeframe before the STIS failure occurred.)
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This item will require resources from ESS/Technical Services
Summary Document: The STIS Experience (Usage: 100%)
(PRIORITY: High)
This activity involves the writing of a document that summarizes our experience with the operation and calibration of
the instrument. It will include sections on the MAMAs, the CCD, the Optics, etc. There will be many references to
other available reports (e.g., ISRs, TIRs), but all kept in one document to provide an easy reference for comparisons
with the operation and calibration of similar detectors in other (present and future) HST instruments.
Acknowledgments. At the time this document was written, the STIS Team consisted of the following members (in
alphabetic order): Alessandra Aloisi, James Davies, Rosa Dı́az-Miller, Linda Dressel, Paul Goudfrooij (Team Lead),
Jessica Kim Quijano, Jesús Maı́z-Apellániz, and Charles Proffitt. All contributed to this document.
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Appendix
A
Calibration Block Responsibilities
The Calibration Block is responsible for:
1. Coordinating the Calibration Projects, including tracking of the progress and success of the program.
2. Carrying out the analysis of the on-orbit calibration data and translating the resulting information into usable
form. This is primarily reference file updates, but it also includes documentation in the instrument handbook,
instrument science reports, technical instrument reports, and FAQs and Foibles on the STIS web site.
3. Work with the Pipeline Block to maintain an accurate accounting of the current state of calibration accuracies.
4. Producing and publishing a closure report for the Calibration programs of Cycles 11 and 12.
5. Work with the Pipeline Block to continue development of an automated system for producing calibration files.
Priorities for the Closeout Calibration of STIS are:
1. Regular updating of reference files, including darks, biases, delta flats, and basic sensitivity.
2. Informing GOs regularly with information learned from calibration activities and operational experience.
3. Characterizing the optical performance (e.g. LSFs, PSFs, geometric distortions, etc.).
4. Characterizing detector and observation-specific peculiarities (e.g., detector nonlinearities, CTE, fringing, long
wavelength halo, scattered light, etc.).
Within each of these priority groups, calibration priority is in the following order by observing mode:
1. First order prime L grating modes (G140L, G230L, G430L, G750L).
2. Echelle spectroscopy.
3. First order M grating modes.
4. MAMA imaging (broad band first, then narrow band).
5. CCD imaging (broad band first, then narrow band).
6. G230LB and G230MB backup modes.
In addition, on-axis calibrations have higher priority than do off-axis calibrations; i.e., we seek first to establish the
calibrations at field/slit center and thereafter to expand the calibration to two dimensions.
B
Pipeline Block Responsibilities
The Pipeline Block is responsible for the following, working in conjunction with the software programmers in the
Science Support Branch in ESS and the OPUS and CDBS developers.
1. The development and maintenance of the STIS pipeline software, including STSDAS/CALSTIS, Generic
Conversion, and the Keyword database. The Pipeline block provides scientific requirements, participates in
the setting of schedules for the work, and tests software before it is released.
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2. The development and maintenance of post-processing user tools for working with STIS data within STSDAS.
Again the Pipeline block provides scientific requirements, participates in the setting of schedules for the work,
and tests software before it is released.
3. The delivery of calibration reference files to CDBS for use both in and outside of the pipeline.
4. Working with the Calibration Block to develop an automated system for producing calibration files.
5. Track the development of new reference files and see that they delivered in an appropriate format to OPUS/CDBS.
6. Develop test plans and software as appropriate to verify the format and scientific integrity of new reference
files.
7. Keep the group and the scientific community notified of updates to reference files.
8. Document procedures for the proper development and delivery of reference files.
9. Troubleshooting of STIS data which has gone to ‘trouble’ in OPUS and overall maintenance of a smoothly
operating STIS pipeline.
10. The regular updating for GOs of information about the quality and nature of the calibrated data produced by
the STIS pipeline and the reference files available, as well as the status and plans for the STIS and related
STSDAS software.
11. The maintenance of a clear set of documentation describing the STIS pipeline and STIS software tools within
STSDAS.
C
User Support Block Responsibilities
The User Support Block is responsible for:
1. Help Desk Support regarding questions on STIS, FOS, and GHRS (FOS helpdesk questions should now be
forwarded to the FOS helpdesk at ST-ECF: ecf-poa@eso.org).
2. The smooth operation of the STIS Contact Scientist Program, including:
• Cycle 7 – 13 STIS Post-Observation support.
• Post-Observation and Archival Data Analysis Support for FOS and GHRS.
• Support for Data Analysis Visits by GOs.
3. Documentation, Tracking, and Management:
• Updating of FAQs
• Maintenance of external Data Foibles WWW page.
• Maintenance of internal User Support WWW page.
The STIS help desk schedule can be found at
http://www.stsci.edu/hst/stis/projects/UserSupport/HelpDesk/helpdesk schedule.html.
A list of ”expert” scientists for answering help desk questions on specific topics is available at
http://www.stsci.edu/hst/stis/projects/UserSupport/HelpDesk/experts analysis.html (see also the TIR on help
desk support).
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D
Hardware/Software Block Responsibilities
This Block is responsible for coordinating the infrastructure needs (hardware and software) of the STIS Team.
Specific tasks include:
1. Monitor disk usage and allocate disk space among team members for functional and scientific work.
2. Maintain the team’s suite of software that is used for calibration and analysis work.
3. Prepare requests for needed equipment and software and justification for the requests.
4. Compress, backup and delete files on team disk systems as necessary to preserve disk space.
5. Assist team members as needed in interfacing with CPT to resolve hardware and software problems.
E
Team Management Block Responsibilities
The Team Management Block is responsible for:
1. Developing the STIS Team Plan.
2. Coordinating the ongoing activities of the STIS Team.
3. Representing the STIS Team within the Instruments Division and STScI Management circles and externally
to the HST Project and the STUC.
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